Elevator system

ABSTRACT

An elevator system including an elevator car and a counterweight interconnected via a traction drive arrangement which includes a drive machine and hoist roping. A compensating system, including compensating roping and a compensator sheave, interconnect the car and counterweight, to compensate for the weight of the hoist roping as the elevator car and counterweight move in their respective travel paths. The compensator sheave includes first and second spaced but interconnected rim portions. A guiding arrangement for the elevator car, including first and second guide rails, guides the elevator car in its travel path, with one of the guide rails being disposed between the first and second spaced rim portions of the compensator sheave.

United States Patent Solymos July 29, 1975 I ELEVATOR SYSTEM [57] ABSTRACT [75] Inventor: Frederick Solymos, Glenridge, NJ. [73] Assignee: Westinghouse Electric Corporation, elevatQr sytem inciuding devatof a Pittsburgh, counterweight interconnected via a traction drive arrangement which includes a drive machine and hoist [22] Flled: Sept- 1974 roping. A compensating system, including compensat- [211 AppL No: 510,828 ing roping and a compensator sheave, interconnect the car and counterweight, to compensate for the weight of the hoist roping as the elevator car and [52] US. Cl [87/22; 187/94 counterweight move in their respective travel paths [51] hit. Cl. 1366b 11/00 The compensator sheave incudes first and second [58] new of Search 187/17, spaced but interconnected rim portions. A guiding ar- 187/94- 95 rangement for the elevator car, including first and second guide rails, guides the elevator car in its travel [561 References C'ted path, with one of the guide rails being disposed be- UNITED STATES PATENTS tween the first and second spaced rim portions of the 3,739,821! 6/1973 Cilderman 187/94 compensator sheave.

Primary ExaminerEvon C, Blunk Assistant Examiner-James L. Rowland 8 Claims, 4 Drawing Figures Attorney, Agent, or Firm-D. R. Lackey I06 |23 7 |72 E] IOZ I20 4/ (IZI 150 4 r I74 l22 H I64 I62 I24 I1e \l I30, I 535 t qi I32 D ii I u 11 |34- I36 I y I I We I PATENTEI] JUL 2 9 I975 SHEET FIG. 2.

ELEVATOR SYSTEM BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates in general to elevator systems. and more specifically to new and improved compensating arrangements for elevator systems.

2. Description of the Prior Art Certain traction elevator systems use compensator roping and a compensator sheave to help counterbalance the weight of the hoist ropes, reducing the unbalanced load which the elevator drive machine must accelerate and lift. The locations of the car and counterweight buffers, and guide rails for the elevator car and counterweight, complicate the placement of the counterweight and compensator sheave in the pit. In some arrangements, the vertical central axis of the counterweight is offset from a horizontal line drawn between the elevator car guide rails, and the drive machine as well as its supporting beams must be skewed in order to attach the hoist roping to the centerlines of the car and counterweight. If the compensator sheave is aligned with the counterweight, and its horizontal centerline parallel to but offset from the horizontal line drawn between the elevator car guide rails, the weight of the compensating roping on the elevator car is not equally distributed relative to the vertical centerline to the car. To partially compensate for this eccentric load, additional weight is often added to the bottom of the elevator car at a location selected to at least partially balance the eccentric load. Eccentric loading the elevator car with the compensating roping degrades ride quality and accelerates wear of the guide rollers.

An alternative arrangement of the compensator sheave is to skew the compensator sheave, in a manner similar to the skewing of the drive machine.

It would be desirable to provide substantially balanced compensating loads on the elevator car and counterweight, as applied thereto by the compensating system, while mounting the compensator sheave with its rotational axis substantially perpendicular to a horizontal line disposed between the elevator guide rails. Further it would be desirable to provide such balanced compensating loads and specified orientation of the compensator sheave, without the necessity of adding auxiliary eccentrically disposed weights to the bottom of the elevator car.

SUMMARY OF THE INVENTION Briefly, the present invention is a new and improved traction elevator system, including an elevator car and counterweight interconnected via hoist roping, and a compensation system for the hoist roping. The compensation system includes a compensator sheave having first and second rim portions interconnected and spaced via a hub portion. The spacing of the rim portions, and the diameter of the connecting hub portion, are selected such that the compensator sheave may be disposed with its spaced first and second rim portions straddling one of the guide rails which guide the elevator car in its travel path.

The compensator sheave is disposed with the elevator car guide rail between the spaced first and second rim portions, with the vertical centerlines of the elevator car, counterweight, first and second guide rails, and compensator sheave oriented in a common plane, and with the rotational axis of the compensator sheave substantially perpendicular to such plane. Buffers for the elevator car and/or counterweight may also be disposed between the spaced rim portions of the compensator sheave, if desired.

In a preferred embodiment. the compensating roping is a single rope which extends from the counter-weight to the elevator car via the first rim of the compensator sheave, about a sheave-like compensator rope support carried by the elevator car, and back to the counterweight via the second rim portion of the compensator sheave. The ends of the single compensating rope are shackled to the counterweight.

BRIEF DESCRIPTION OF THE DRAWINGS The invention may be better understood, and further advantages and uses thereof more readily apparent. when considered in view of the following detailed description of an exemplary embodiment. taken with the accompanying drawings, in which:

FIG. 1 is a plan view of an elevator system which illustrates certain prior art compensator arrangements;

FIG. 2 is a perspective view of an elevator system constructed according to the teachings of the invention;

FIG. 3 is a plan view of the elevator system shown in FIG. 2, which additionally includes buffer locations for the elevator car and counterweight which may be used; and

FIG. 4 is an elevational view of the elevator system shown in FIGS. 2 and 3, taken in the direction of arrows IVIV shown in FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, and FIG. 1 in particular, there is shown a plan view ofa traction elevator system 10 which illustrates certain prior art compensating arrangements. Elevator system 10 includes an elevator car 12, a counterweight l3, and means (not shown) mounting the car 12 and counterweight 13 for move ment in a hoistway 14 of a structure or building having a plurality of floors, indicated generally at 16, which floors are served by the elevator car 12. The mounting means includes a traction drive machine, a traction drive sheave, and hoist roping. The hoist roping is reeved over the drive sheave, and its ends are connected to the elevator car and counterweight.

First and second elevator car guide rails, 20 and 22, disposed at opposite sides of the elevator car 12, cooperate with guide roller assemblies (not shown) carried by the elevator car, to guide the elevator car 12 in its vertical travel path. A horizontal line 24 drawn between the vertical longitudinal axes of the elevator car guide rails 20 and 22, intersects the vertical centerline 26 of the elevator car 12.

First and second counterweight guide rails 28 and 30, disposed at opposite ends of the counterweight 13, cooperate with guide roller assemblies (not shown) carried by the counterweight 13, to guide counterweight 13 in its vertical travel path. A horizontal line 32 drawn between the vertical longitudinal axes of guide rails 28 and 30 is perpendicular to the horizontal line 24 drawn between the guide rails of the elevator car, but it will be noted that the vertical centerline 34 of the counterweight 13 is displaced from the vertical plane of which line 24 is an edge. This vertical plane includes the vertical centerline 26 of the elevator car 12 and the vertical longitudinal axes of the elevator car guide rails and 22. A horizontal line drawn perpendicular to line 32 which passes through vertical centerline 34 of the counterweight 13 is horizontally spaced from the line 24 by a dimension indicated by reference number 36.

Compensation for the weight of the hoist roping is provided by a first compensating arrangement, shown in solid lines. which arrangement includes at least a pair of compensator ropes indicated at 38 and 40. The compensator rope 38 and 40 extend from the bottom of the elevator car 12 to the bottom of the counterweight. hanging therefrom to provide loops in the pit at the bottom of the hoistway 14. The compensator sheave 42 hangs in the bights of the loops to tension and guide the rope 38 and 40.

First and second compensator sheave guide rails 44 and 46 are disposed on opposite sides of the compensator sheave 42 such that a horizontal line drawn between the longitudinal axes thereof coincides with the rota tional axis 48 of the compensator sheave 42. The central vertical axis 50 of the compensator sheave 42 falls upon the horizontal line 35. First and second spaced car buffers 52 and 54 may be disposed in the pit with their vertical axes falling on the horizontal line 24, with these buffers being equally spaced from the centerline 26 of the elevator car 12. Alternatively, a single car buffer 56, shown in phantom, may be disposed such that its vertical longitudinal axis coincides with the vertical centerline 26 of the elevator car 12.

In like manner, first and second counterweight buffers 58 and 60 may be disposed in the pit with their vertical axes falling on horizontal line 32, with these buffers being equally spaced on opposite sides of the vertical centerline 34 of the counterweight. Alternatively, a single buffer 62, shown in phantom, may be disposed such that its vertical longtitudinal axis coincides with the vertical central axis 34 of the counterweight 13, if the compensator sheave 42 is dimensioned to clear a buffer disposed in this location.

The compensating ropes 38 and 40 each provide a downward force on the counterweight 13, which acts through, or is effectively located along the vertical centerline 34 of the counterweight. The ropes 38 and 40 however, are connected to the elevator car 12 in a manner which provides an unbalanced force on the bottom of the elevator car, as the ropes are spaced from the vertical centerline 26 of the elevator car, in the same direction from centerline 26, providing a resultant downward force at 64, which is the intersection of a horizontal line 66 drawn through the vertical axes of the ropes 38 and 40 as they extend downwardly from the elevator car, and the horizontal line 35.

The eccentric downward force which acts through vertical centerline 64 may be partially offset by adding a weight 68 to the bottom of the elevator car which acts through a vertical centerline 70, which is also disposed on line 66, the same distance from the vertical centerline 26 of the elevator car as vertical line 64, but on the opposite side of the centerline 26. The weight 68 is only a partial compensation, as the downward force which acts along vertical line 64 changes as the car and counterweight move in the hoistway, while the weight 68 is a fixed weight. The weight 68 also adds additional cost to the elevator installation.

An alternative compensating arrangement, which uses a sheave grooved to accommodate car buffer 56 and counterweight buffer 62, is shown in FIG. 1 with the broken lines. In this arrangement. the compensator sheave, referenced 42. is oriented such that the horizontal centerline 35 of a compensator sheave 42 forms a predetermined acute angle, referenced 72, with a horizontal line drawn between the elevator car guide rails 20 and 22. In other words. the compensator sheave is skewed in a manner similar to the skewing of the drive machine. in order to provide balanced compensating loads on both the car and counterweight.

FIGS. 2, 3 and 4 illustrate an elevator system constructed according to the teachings of the invention, in which balanced compensating loads are applied to the car and counterweight without the necessity of skewing the drive machine or the compensator sheave. FIG. 2 is a perspective view of the elevator system 100, FIG. 3 is a plan view, and FIG. 4 is an elevational view taken in the direction of arrows lVlV. as illustrated in FIG. 3.

More specifically, elevator system 100 includes an elevator car 102 mounted for movement in a hoistway 104 of a structure or building having a plurality of floors, indicated generally at 106, which floors are served by the elevator car 102. An elevator drive motor 108 may be mounted on the floor of a penthouse in the building, with the drive motor 108 having a drive shaft 110 to which a traction drive sheave 112 is secured.

Hoist ropes or cables 114 interconnect the elevator car 102 with a counterweight 116. The hoist rope 114, in this embodiment of the invention, interconnects the elevator car 102 and counterweight 116 with a l to I roping arrangement. but any roping arrangement may be used. First and second elevator car guide rails 117 and 119, disposed at opposite sides of the elevator car 102, cooperate with guide roller assemblies (not shown) carried by the elevator car, to guide the elevator car in its vertical travel path. As illustrated in FIG. 3, a horizontal line 123 drawn between the vertical longitudinal axis of the guide rails 117 and 119 intersects the vertical centerline 125 of the elevator car 102.

First and second counterweight guide rails and 132 disposed at opposite ends of the counterweight 116, cooperate with guide roller assemblies (not shown) carried by the counterweight, to guide the counterweight in its vertical travel path.

Unlike the prior art arrangement shown in FIG. 1, it will be noted that the vertical centerline 136 of the counterweight 116 falls on the horizontal line 123 drawn between the vertical axes of the elevator car guide rails 117 and 119. Thus, the traction drive machine 108 and its supporting beams in the penthouse are not skewed, simplifying the construction of the drive machine supporting structure in the penthouse.

Compensation for the weight of a hoist rope 114 is provided by compensator roping 120 and 121, and a weighted compensator sheave 122 disposed below the travel path of the car 102 in the bottom portion of the hoistway 104, which is commonly referred to as the pit. The compensator sheave 122 is mounted for rotation about its axis 124.

Compensator roping 120 and 121 may be two separate ropes, the ends of which are shackled to the eleva tor car and counterweight. In a preferred embodiment as disclosed in my co-pending application, Ser. No. 341,645, filed Mar. 15, I973, which application is assigned to the same assignee as the present application, the roping 120 and 121 represents a single rope, the ends of which are shackled only to the counterweight 116. A loop is formed by the single rope and the loop end is reeved about a support 130 carried by the elevator car 102, with the sides of the loop, indicated by rope portions 120 and 121, proceeding from the support 130 to the counterweight 116 via the compensator sheave 122. Support 130 is designed to enable the tensions in the two portions of the single rope to continuously equalize as the elevator system is being used.

As best illustrated in FIGS. 3 and 4, the compensator sheave 122 includes first and second spaced rim portions 148 and 150, respectively, each of which has a substantially U-shaped groove disposed about its outer circumference for receiving portions 120 and 121 of the compensator rope, as these rope portions extend downwardly from the compensator support 130 to the compensator sheave 122.

Portions 120 and 121 of the compensator rope extend about the rims 148 and 150, respectively, of the compensator sheave 122 and are directed upwardly to the counterweight 116 where they are attached, such as by shackles 152 and 154.

The spaced rim portions 148 and 150 of the compensator sheave 122 are interconnected via a hub portion 160. According to the teachings of the invention, the hub portion 160 is dimensioned in length and outside diameter to receive the car guide rail 119, which permits the vertical centerlines 125 and 136 of the elevator car and counterweight, respectively, to fall upon the line 123 drawn through the vertical longitudinal axes of the elevator car guide rails 117 and 119. The rim portions 148 and 150 may be like iron castings, with the like castings being held in assembled relation by the hub portion 160. The hub portion 160 may be a tubular member found of steel. The compensator sheave 122 is guided in a vertical travel path by guide rails 162 and 164, to allow the compensator sheave to move up and down as required to maintain tension on the compensating roping as the hoist ropes stretch and contract, and a suitable lock-down arrangement 166 may be provided, such as disclosed in my co-pending application Ser. No. 347,285, filed Apr. 2, 1973, now US. Pat. No. 3,835,959. It will be noted that the vertical central axis 169 of the compensator sheave 122 lies on the horizontal line 123 drawn through the elevator car guide rails.

A single buffer 170 oriented with its vertical longitudinal axis coinciding with the vertical centerline 125 of the elevator car 102, or two buffers 172 and 174 may be provided for the elevator car, with the buffers in the latter arrangement disposed on opposite sides of the centerline 125 along the line 123 which is drawn through the elevator car guide rails. If two buffers are provided, the length of the hub 160 should be selected such that the rim portion 148 and 150 will straddle the buffer 174 without interference, as well as straddling the guide rail 119. The hub portion should also be dimensioned to receive a car buffer if only a single buffer 170 is used, if the diameter of the compensator sheave is selected such that the single buffer 170 would interfere with the compensator sheave 122.

A single buffer 176 may be provided for the counterweight 116, oriented with its vertical longitudinal axis coinciding with the vertical centerline 136 of the counterweight 116; or, two buffers 178 and 180 may be provided, disposed on opposite sides of vertical line 136, and oriented to fall on the horizontal line 134 drawn through the vertical longitudinal axes of the counterweight guide rails 130 and 132. If a single counter- 6 weight buffer 176is used, the hub 160 should be dimensioned to accommodate the buffer between the spaced rim portions 148 and 150.

in summary, elevator system presents a new and improved mounting arrangement for the elevator car 102, counterweight 116 and compensator sheave 122 wherein their vertical central axes 125, 136 and 169, respectively. are oriented in a common vertical plane. of which the horizontal line 123 drawn through the vertical longitudinal axes of the elevator car guide rails 117 and 119 is an edge. Further. the rotational axis 124 of the compensator sheave is perpendicular to this vertical plane. This arrangement, wherein an elevator car guide rail is disposed between spaced rim portions of the compensator sheave, permits vertical. balanced. compensating loads to be applied to both the elevator car and counterweight, while making it unnecessary to skew the drive machine and compensator sheave relative to a horizontal line drawn through the vertical longitudinal axes of the elevator car guide rails.

I claim as my invention:

1. An elevator system, comprising:

an elevator car,

a counterweight,

means including traction drive means and hoist roping mounting said elevator car and counterweight for movement in a predetermined travel path,

means guiding the movement of said elevator car including first and second guide rails,

a compensator sheave disposed below the travel path of said elevator car,

and compensating rope means interconnecting said elevator car and counterweight via said compensator sheave,

said compensator sheave including first and second rims interconnected and spaced via a hub portion with said compensator sheave being disposed such that its first and second spaced rims straddle one of the first and second guide rails.

2. The elevator system of claim 1 wherein the elevator car, counterweight, compensator sheave, and first and second guide rails are oriented with their vertical central axes in a common vertical plane, with the rotational axis of the compensator sheave being substantially perpendicular to the vertical plane.

3. The elevator system of claim 1 including compensator rope support means carried by the elevator car, and wherein the compensator rope means is a single rope arranged to provide a loop having first and second ends, with the loop of the single rope being disposed about said compensator rope support means, and with the first and second ends of the single rope extending to the counterweight about the first and second rims, respectively, of the compensator sheave.

4. The elevator system of claim 3 including means attaching the first and second ends of the single rope to the counterweight.

5. An elevator system, comprising:

an elevator car,

a counterweight,

means including traction drive means and hoist roping, mounting said elevator car and counterweight for movement in a predetermined travel path,

a compensator sheave including first and second spaced rim portions, interconnected via a hub portion,

said compensator sheave being disposed below the travel path of said elevator car.

first and second guide rails for guiding the movement of said elevator car. said first and second guide rails being disposed at opposite sides of said elevator car with one of said guide rails being disposed between the first and second spaced rims of said compensator sheave.

and compensator rope means interconnecting said elevator car and counterweight via said compensator sheave.

6. The elevator system of claim wherein the elevator car. counterweight, compensator sheave. and first and second guide rails are oriented with their vertical central axes in a common vertical plane, with the rotational axis of the compensator sheave being substantially perpendicular to the vertical plane.

Y 7. The elevator system of claim 5 including compensator rope support means carried by the elevator car, and wherein the compensator rope means is a single rope arranged to provide a loop having first and second ends. with the loopof the single rope being disposed about said compensator rope support means and with the first and second ends of the single rope extending to the counterweight about the first and second rims. respectively. of the compensator sheave.

8. The elevator system of claim 7 including means attaching the first and-second ends of the single rope to the counterweight. 

1. An elevator system, comprising: an elevator car, a counterweight, means including traction drive means and hoist roping mounting said elevator car and counterweight for movement in a predetermined travel path, means guiding the movement of said elevator car including first and second guide rails, a compensator sheave disposed below the travel path of said elevator car, and compensating rope means interconnecting said elevator car and counterweight via said compensator sheave, said compensator sheave including first and second rims interconnected and spaced via a hub portion with said compensator sheAve being disposed such that its first and second spaced rims straddle one of the first and second guide rails.
 2. The elevator system of claim 1 wherein the elevator car, counterweight, compensator sheave, and first and second guide rails are oriented with their vertical central axes in a common vertical plane, with the rotational axis of the compensator sheave being substantially perpendicular to the vertical plane.
 3. The elevator system of claim 1 including compensator rope support means carried by the elevator car, and wherein the compensator rope means is a single rope arranged to provide a loop having first and second ends, with the loop of the single rope being disposed about said compensator rope support means, and with the first and second ends of the single rope extending to the counterweight about the first and second rims, respectively, of the compensator sheave.
 4. The elevator system of claim 3 including means attaching the first and second ends of the single rope to the counterweight.
 5. An elevator system, comprising: an elevator car, a counterweight, means including traction drive means and hoist roping, mounting said elevator car and counterweight for movement in a predetermined travel path, a compensator sheave including first and second spaced rim portions, interconnected via a hub portion, said compensator sheave being disposed below the travel path of said elevator car, first and second guide rails for guiding the movement of said elevator car, said first and second guide rails being disposed at opposite sides of said elevator car with one of said guide rails being disposed between the first and second spaced rims of said compensator sheave, and compensator rope means interconnecting said elevator car and counterweight via said compensator sheave.
 6. The elevator system of claim 5 wherein the elevator car, counterweight, compensator sheave, and first and second guide rails are oriented with their vertical central axes in a common vertical plane, with the rotational axis of the compensator sheave being substantially perpendicular to the vertical plane.
 7. The elevator system of claim 5 including compensator rope support means carried by the elevator car, and wherein the compensator rope means is a single rope arranged to provide a loop having first and second ends, with the loop of the single rope being disposed about said compensator rope support means and with the first and second ends of the single rope extending to the counterweight about the first and second rims, respectively, of the compensator sheave.
 8. The elevator system of claim 7 including means attaching the first and second ends of the single rope to the counterweight. 